Imagick::getIteratorIndex()

(PECL imagick 2.0.0)

Gets the index of the current active image

说明

Imagick::getIteratorIndex(void): int

Returns the index of the current active image within the Imagick object.此方法在Imagick基于ImageMagick 6.2.9以上版本编译时可用。

返回值

Returns an integer containing the index of the image in the stack.

错误／异常

错误时抛出 ImagickException。

范例

Example #1 Using Imagick::getIteratorIndex():

Create images, set and get the iterator index

<?php
$im = new Imagick();
$im->newImage(100, 100, new ImagickPixel("red"));
$im->newImage(100, 100, new ImagickPixel("green"));
$im->newImage(100, 100, new ImagickPixel("blue"));
$im->setIteratorIndex(1);
echo $im->getIteratorIndex();
?>

参见

• Imagick::setIteratorIndex() Set the iterator position
• Imagick::getImageIndex() Gets the index of the current active image
• Imagick::setImageIndex() Set the iterator position

This will also retrieve which page number of a multipage document (i.e. PDF, PS) file the Imagick instance is currently on. By default for a PDF it seems to be set to the last page.

The getIteratorIndex function of the ImageMagick function works on any type of image, but it is built for measuring the number of frames in an animated .gif file. For non-animated image files, like regular .bmp or .jpg files, this function will always return the number '0', meaning that there is only one frame. Counting starts from zero with this function, so a .gif file with five different frames will return a value of '4' on this. Highly repetitive, but psychedelic animated GIF's are often anywhere between 10 and 30 frames, but a .gif file that is nothing more than video footage converted to a datafile may have hundreds of frames.
According to Wikipedia (in the article for "Graphics Interchange Format"), an animated GIf image is a uses the GIF standard "which allows various images (frames) in the file to be painted with time delays." This function won't get you the amount of time that delays between each frame, but it will give you the number of unique frames in a .gif file. This will tell you how complicated or simple the animation may be.
Is the 'getIteratorIndex' function not working for you? Try the 'getImageIndex' function, which produces the same exact result.
Some sample code :
<?php
      // Author: holdoffhunger@gmail.com
  
    // Imagick Type
    // ---------------------------------------------
  $imagick_type = new Imagick();
  
    // Open File
    // ---------------------------------------------
    
  $file_to_grab = "image_workshop_directory/test.gif";
  
  $file_handle_for_viewing_image_file = fopen($file_to_grab, 'a+');
  
    // Grab File
    // ---------------------------------------------
  $imagick_type->readImageFile($file_handle_for_viewing_image_file);
  
    // Get Image Type Value
    // ---------------------------------------------
    
  $image_iterator_index = $imagick_type->getIteratorIndex();
  
    // Print Image Type Value
    // ---------------------------------------------
    
  print("Number of Unique Frames in the .GIF File: $image_iterator_index");
?>